Light wavelength shifter

Abstract

An optical waveguide type light wavelength shifter device has a core made of a nonlinear optical crystal and a cladding. The optical waveguide type light wavelength shifter device is provided with a thermoelectric element so that wavelength variation of the second harmonic wave resulting from a variation in the wavelength of an incident light can be minimized.

What is claimed is: 
     
       1. A light wavelength shifter device comprising: an optical waveguide type light wavelength shifter element which comprises a core of a nonlinear optical crystal having a varying rate of refractive index with respect to temperature higher than 1×10 -4  /° C., and a cladding in contact with the core so that a primary incident light on the core can be shifted to a second harmonic wave having a wavelength of half the wavelength of said primary incident light; and   a thermoelectric element in contact with said optical waveguide type light wavelength shifter element.   
     
     
       2. A light wavelength shifter device as claimed in claim 1, wherein said thermoelectric element is made of a Peltier device whose generation and absorption of heat are regulated by a supplied electric current.